Driving apparatus for crawler type vehicles



Aug. 3, 1943. v c. w. LEGUILLON DRIVING APPARATUS FOR CRAWLER TYPEVEHICLES Filed May 31, 1941 V jL/E'fifaa 5555/2 Ulgyuj/an Patented Aug.3, 194a DRIVING APPARATUS FOR CRAWLER TYPE VEHICLES Charles W.Leguillon, Akron, Ohio, assignor to The B.- F.'Goodricli Company, NewYork, N. Y., a corporation of New York Application May 31, 1941, SerialNo. 395,951

Gaims.

This invention relates to driving apparatus for crawler type vehicle orvehicles of the self-laying track type.

Heretoiore, devices of the crawler type have been of such constructionthat they have required accurate machining of metallic parts, as

it has been the purpose usually to provide accu-' rately spaced drivingteeth or sprockets on the drive wheel and to provide accurately spacedmeans on the flexible track for cooperation with the driving teeth.Small deviations from the proper fit of the parts often have resulted infaulty performance or undesirable noisy operation, and the constructionoften has been very costly to produce.

- The principal objects of the invention are to provide drivingapparatus in which the driving load is transmitted between the drivingwheel and the flexible track by wedging means, to provide formaintaining the driving engagement by tensioning of the track, toprovide a self-energizing driving engagement,- to provide quietoperation, to provide for effectively guiding the track, to reduce oreliminate parts that require accurate machining, to provide strongdriving traction, and to provide simplicity of construction 'andconvenience of manufacture. These and other objects will appear from thefollowing description and the accompanying drawing.

Of the drawing: Fig. 1 is a side elevation of drivlngapparatusconstructed according to and embodying the invention, parts being brokenaway.

Fig. 2 is a plan view showing the wheel-contacting face of a portion ofthe track of Fig. 1-,

' other portions being broken away.

Fig. 3 is a cross-sectional view taken on line- 33 of Fig. 1.

Fig. 4 is a side view of a portion of one of the drive wheels and thetrack to a larger scale showing the track as tensioned in use.

Fig. 5 is a view like Fig, 2 but-showing-a modified construction.

Fig. 6 is a sectional view like Fig. 3'but showing the track of Fig. 5and its cooperating drive wheel, the section being taken on line 6 6 ofby an increase of tension in the track. One or both of the engagingsurfaces ofthe track and' wheel are preferably of resilient material andone or both of such surfaces are inclined to the direction of travel ofthe track in a manner to provide the wedging action.

Referring to the embodiment of Figs. 1 to 4 of the drawing. the numerall0 designates a drive wheel, I I an idler wheel, and I2 the flexibletrack extending thereabout. The drive wheel is fixed to a shaft l4journaled in bearings l5 fixed to the frame It of the vehicle. Shaft I4is driven from the power plant of the vehicle in any desired manner. Thetrack may be also guided by bogie wheels 40,. 4| mounted on the frameI6.

The idler wheel II is fixed to an idler shaft l1 journaled in bearingsl8 mounted on the frame IS. The bogie wheels are also freely rotatableon their shafts 42, 43.

The flexible track preferably comprises spacedapart tension members inthe form of substan-' tially non-stretchable metallic cables 20 held inlaterally spaced-apart relation by cross-bars 2| each comprising a pairof elements 22, 23 having complementary grooves '24 for receiving thecables. Each cable is enclosed by a cushion layer 25 of rubber-likematerial whichcushions it resiliently from the cross-bars and transmitsthe driving force between the bars and the cables. Guiding elements'26,26 may be mounted on the cross-bars, if desired, for keeping the trackaligned on the wheel. i

The cables and the cross-bars are preferably completely enclosed by aresilient body 30' of rubber-like material. The cables may be arrangedin two spaced-apart groups, as in Fig. 3, and the resilient body may beseparated longitudinally to provide two spaced-apart bodies 3|, 32separated by a space 33 across which the bars 2| extend.

The wheel-contacting face of the track is formed with cross grooves 34,35 adapted to cooperate with driving elements which elements may be inthe form of ribs 36 extending across the face of the drive wheel. Eachcross groove has load-transmitting facesfla, 34b, at its leading andtrailing margins, which are inclined to the direction of motion of thetrack, so as to present smooth inclined surfaces to be engagedrespectively by surfacees 36a, 36b, of the driving wheel ribs, accordingto the direction of travel, Ior transmitting the load between the drivewheel and the track by a-wedging action. This wedging action, by itstendency to enlarge the endless track, results in an increase ofpressure on porting surface to the bogie wheels.

the wedging surfaces and some sliding thereof until a balance of forcesis attained to resist further slippage of the surfaces by shear stressesin the parts. Thus, the track is maintained on the driving wheels by aself-energizing action under the driving force.

These cross grooves the face of the track but preferably are disposeddiagonally thereof in opposite directions in herringbone fashion asshown in Fig. 2, so that they act simultaneously to guide and center thetrack as well as to transmit the driving load thereto,- while at thesame time presenting a smooth sup- Where the track has a divided rubberbody, as in the embodiment of Fig. '3, additional guiding means may beprovided in the form of metallic lugs 26 secured to the cross-barsbetween the rubber bodies 3|, 32 and adapted to guide the track byengaging within a groove 45 formed at the center of the face of thedrive 'wheel, and similar central guiding grooves 46, 41, 48 areprovided in the idler and bogie wheels for guiding purposes.

The metal cables resist stretching of the track and hold thepitch of thegrooves relatively uniform, while at the same time the cushioningmaterial provides a cushioned drive which permits use of cast drivingwheels and makes unnecessary the use of accurately machined wheels. Thedrive is relatively noiseless because of the rubber-to metal contact ofthe wheel and track.

While it is preferred to employ grooves well spaced from each other,providing extensive reaches of relatively flat wheel-supporting surfacebetween them, the grooves may if desired be relatively close togetherand may have humped portions therebetween, and the entirewheel-contacting surface of the track or the track-contacting surface ofthe wheel may even have a contour of or approximating a sine curve, asshown at El in Fig. '7 wherein 60 designates the track.

By the provision of a multiplicity of closelyspaced driving grooves anddriving elements on the wheel and track cooperating with each othersubstantially positive driving without undesirable slippage is provided,since for slippage to an apex at the center of the track as shown andthe driving lugs on the wheel may be similarly disposed orterminated.short of the apex to assure an even distribution of pressurealong the wedging surfaces. ,In addition to the guiding effected by theherringbone arrangement of the grooves, or in lieu of such guiding incase it is desired to dispose the grooves straight across the track, theWheel 54 may be provided with marginal flanges 55, 55 overlying thesides of the track. Such side guiding flanges may be incorporated alsoin the embodiment of Figs. 1

to 4, if desired to supplement or replace the cen-' ter guiding lugs.

Variations may be made without depart g may extend straight across fromthe scope of the invention as it is defined by the following claims. 1

I claim: i

1. Driving apparatus for a self-laying tracktype vehicle, said apparatuscomprising a drlving wheel and a flexible endless track comprising anextensive flexible tension' resisting element extending along saidtrack,.said track being trained about said wheel, said wheel and trackeach having a plurality of surface portions cooperable in pairs, one ofthe pair being on the wheel and the other on the tract:v and the surfaceportions of the'pair being inclined obliquely to a plane tangential tothe wheel at the surface portions during engagement in a manner to drivethe track and also to support the track upon the wheel both through theengagement ofpthe same pair of surface portions and to provideengagement of such surface portions by a wedging action tending to urgethe track outwardly from the wheel and thereby tending to imposeincreased tension in the track under the driving force. a 2.;Drivingapparatus for a self-laying tracktype vehicle, said apparatus comprisinga driving wheel and a flexible endless track trained about said wheel,said wheel and track each having a plurality of surface portionscooperable in pairs, onev of the pair being on the wheel and the otheron the track, at least one of the pair of surfaceportions being ofresilient rubber.-

like material and the surface portions of the pair.

being inclined obliquely to a plane tangential to the wheel at thesurface portions duringengagement in a manner to provide engagement ofsuch surface portions of the pair by a resilient wedging action tendingto urge the track outwardly from the wheel and thereby tendingresiliently to impose increased tension in the track under the drivingforce.

3. Driving apparatus for a self-laying tracktype vehicle, said apparatuscomprising a driving wheel and a flexible endless track trained aboutsaidwheel, said wheel and track each having a plurality of surfaceportions cooperable in pairs, one of the pair being on the wheel and theother on the track and the surface portions of the pairbeing inclinedobliquely to a plane tangential to the wheel at the surface portionsduring engagement in a manner to drive the track and also to support thetrack upon the wheel both through the engagement of the same pair ofsurface portions and to provide engagement of said surface-portions by awedging action tending to urge the track outwardly from the wheel andthereby tending to impose increased tension in the track under thedriving force, the surface portions being provided by continuoussmo'othly sinuous surfaces on the wheel and track.

4. Driving apparatus for a self-laying tracktype vehicle, said apparatuscomprising a driving wheel and a flexible endless track trained aboutsaid wheel, said wheel and track each having a plurality of surfaceportions cooperable in pairs, one of the pair being on the wheel and theother on the track and at least one of the pair being of resilientrubber-like material and the surface portions of the pair being inclinedobliquely to a plane tangential to the wheel at the surface portionsduring engagement and also obliquely in such plane in herringbonefashion in a manner to drive the said surface portions by a. wedgingaction tending to impose increased tension in the track under thedriving force. a

5. Driving apparatus for a self-laying tracktype vehicle, said apparatuscomprising a driving wheel and a flexible endless track trained aboutsaid wheel, said track being centrally divided to provide axiallyspaced-apart flexible bands, said wheel and said track each having apluralityoi. 10

surface portions cooperable in pairs, one of the pair being on the wheeland the other on the track and the surface portions or the pair beinginclined obliquely to a plane tangential to the wheel at the surfaceportions during engagement and also obliquely in such plane in oppositedirections in the respective bands of the track in herringbone fashionin a manner to 1 drive the track and also to support the track upon thewheel both through the engagement oi the same pair of surface portionsand to provide engagement of such surface portions by wedging actiontending to urge the track outwardly from the wheel and thereby tendingto impose increased tension in the track under the driving force.

CHARLES W. LEGUILLON.

